Acceleration hesitation after turning on when warm

Hey all I’ve been racking my brain with this for a few months. I’ve done a lot of research and I have no prior experience with working on a vehicle so I’m kind of stuck on where to go next.

I have a 2004 3.4 4x4 automatic double cab with just about 268k miles. When I start it up in the morning or when I leave for work after it’s been sitting it drives smooth. It doesn’t happen all the time. Let’s say after I leave work, I drive 10 - 30 min and stop at a store. I turn it on and as I’m leaving I notice that when I press on the gas it hesitates, moves slowly and sounds louder like it’s pulling in a lot of air or not getting enough air (but I have no idea what’s really happening). Once I get going it kicks in and seems better but still more sluggish. It doesn’t not do it when going from a stop in traffic or a stop sign, only when going from park to drive.

I’ve dug through all the posts from over the years and have done what was recommended without spending too much money. I’ve cleaned the MAF, replaced the TPS and air filter, took off the throttle body and cleaned it, replaced PCV valve, grommet and tube and changed spark plugs and wires. I was sure it was a TPS issue but that didn’t help.

I put 2 bottles of seafoam in the gas tank about a month ago and I didn’t notice it happening throughout that whole tank which leads me to think maybe it is gunked up somewhere? But could have just been coincidence.

I bought it at the end of July. I have the carfax and at the beginning of the year the valve cover and intake manifold gaskets were replaced. At the end of last year the fuel system was cleaned and serviced and the fuel filler hose/pipe were replaced along with the charcoal canister. I am due for a new timing belt since it says it was last changed at 108k. Could that be something that could cause this?

I’d love to hear what people who are more experienced have to say about what would be my next thing to check or to have looked at. Sorry for the long post and I appreciate it!

 

Has it caused your Check Engine light to trip??

If so have you pulled any codes??

I never learned to drive a Automatic Transmission but it sounds like you might have a shifting issue since it seems to only happen going from park to drive just a guess!

 

Might benefit from new plugs and wires

 

Sounds like you're missing some lead.

Spoiler

In your foot.

 

Sorry, just finished reading that you’ve already done that

 

Maybe the coils are starting to fail, vacuum leak? Hard to say without experiencing it from the driver’s seat.

 

If your timing belt failed you would know because your valves will be bent from slapping pistons. It’s not a part that gives warning.

 

3.4 is a non interference engine.

The only problems might come from what ever damage the timing belt might cause getting jammed against the sprockets and etc if it failed going down the road at 60 mph.

 

Gotta love intermittent problems....How does your throttle body look? I know you said you cleaned, but is it worn?Have you tested the TPS?
Were the MAF and IAC factory replacements?
x2 on a vac leak. Replace every vac line one at a time.
You are wayyyyy overdue for a timing belt change.
I have some similar issues and this is what a worn TB looks like.

 

Went through similar with a P0171 code on top of that...it ended up being the fuel pressure regulator. Btw...when you cleaned the throttle body, did you also clean out the IAC?

 

The throttle body definitely looked pretty worn and dirty. I did notice when I cleaned it, it idled a lot higher and there was a gap between the butterfly and the edge. I didn’t replace the MAF just cleaned it so I don’t know if or when it was replaced. I could look at it and see what model it is. This year doesn’t have an IAC.

Im planning on getting he timing belt done I’m just low on cash rn due to reduced hours at work.

I’m just leaning so how do I know what the vacuum lines are?

 

The coils are something I’ve been thinking about for sure.I agree, it’s hard to explain as being the person from the drivers seat.

 

the best advice I can give is take it to a shop or find a mobile diagnostician. Many people have tried to save money by diagnosing and fixing issues but end up spend lots more money by throwing parts at the vehicle. Having scan tool(s) is one thing, interpreting what it is telling you is another. I am sure that if you tell us what sity you live in people on the forum can tell you of a decent shop.

 

This TB doesn’t have the IAC valve. It’s the electronic controlled version.

 

When I cleaned my throttle body, my idle increased as well. I am pretty sure that you do have a IAC, someone can correct me if I am wrong. When you cleaned the TB did you remove it from the vehicle? There is no other way to do this. AND if you cleaned it on the vehicle, all of the crap went into the IAC. Watch timmy the toolmans video for info. There is a factory service manual on this site to find vac lines. Some of mine were hard as rocks.

 

Here’s couple TB pics after it was cleaned.

 

Yeah I’m thinking that since I only know so much. I live in Westminster, CO which is about 15 min from Denver

 

@Pithy is correct. the 03-04 do not have a separate IAC like the 95-02. These are electronic TB.

That gap would cause higher idle but it definitely should cause stuttering.

see if there is any codes. my truck right now as of Tuesday has a cylinder misfire that I need to pinpoint to either a coil pack or plug/wire issue.

my MIL/check engine light actually went "out" when I started having the problem (go figure) but my uncle was able to pull a P0302 with his SnapOn scanner and we watched it

I'm going to check my little BT module and see if I can get the same code, then switch the pack to a different spot. I'll see if it follows the spot.

 

I haven’t gotten any CEL codes recently. When I first got it, the light came on and was a cylinder misfire. That’s when I replaced the spark plugs and that solved that issue. Changes the wires just haven’t done the coil packs

 

Christopher, for what its worth you may be able to adjust your throttles resting position to be more closed.

also, I have had my maf sensor get lazy, and even cleaning didn’t help. It caused hesitation because it wasn’t really registering all the air coming through when the throttle opened. As a result the computer didnt put enough fuel in and it hesitated and lacked power.